Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
  • C23C14/0641—Nitrides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
  • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
  • C23C14/3485—Sputtering using pulsed power to the target
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
  • C23C14/35—Sputtering by application of a magnetic field, e.g. magnetron sputtering
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C30/00—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process
  • C23C30/005—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process on hard metal substrates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
  • B22F2005/001—Cutting tools, earth boring or grinding tool other than table ware

Definitions

• the present invention relates to a coated cutting tool particularly suitable for cutting especially hard workpiece materials (iso-H materials).
• the cutting tool has a coating comprising a (Ti,AI,Cr,Si)N layer.
• cutting tools for metal machining comprises a substrate of a hard material such as cemented carbide, and a thin wear resistant coating deposited on the surface of the substrate.
• a hard material such as cemented carbide
• a thin wear resistant coating deposited on the surface of the substrate.
• cutting tools are cutting inserts, drills or endmills.
• the coating should ideally have a high hardness but at the same time possess sufficient toughness in order to withstand severe cutting conditions as long as possible.
• One group of workpiece materials are hardened materials such as hardened steel, chilled cast iron and white cast iron. This group of materials is classified as iso-H materials. They are especially hard and difficult to cut due to the high cutting forces needed. Materials belonging to the iso-H group generate a lot of heat during the cutting operation. Also there is a high level of wear on the cutting edge.
• US 2015/0232978 A1 discloses a coated cutting tool with a coating comprising a multilayer of sub-layers of (Ti,AI)N, (AI,Cr)N and (Ti,Si)N, the average composition being about Ti0 . 45AI0 . 40Cr0 . 10Si0 . 05N.
• the coating is deposited by cathodic arc
• EP 3434809 A1 discloses a coated cutting tool with a (Ti,AI,Cr,Si)N coating comprising a multilayer of sub-layers of (Ti,Si)N and (AI,Cr)N.
• the coating is deposited by cathodic arc evaporation.
• the object of the present invention is to provide a coated cutting tool with excellent high-temperature stability and improved tool life, especially when cutting iso- H workpiece materials.
• Figure 1 shows an electron diffraction image of a (Ti,AI,Cr,Si)N layer according to the invention.
• Figure 2 shows a radial intensity distribution curve for an electron diffraction image of a (Ti,AI,Cr,Si)N layer according to the invention.
• Figure 3 shows an averaged radial intensity distribution curve for an electron diffraction image of a (Ti,AI,Cr,Si)N layer according to the invention.
• Figure 3a shows an enlarged part of an averaged radial intensity distribution curve for an electron diffraction image of a (Ti,AI,Cr,Si)N layer according to the invention.
• Figure 4 shows an X-ray theta-2theta diffractograms for a (Ti,AI,Cr,Si)N layer according to the invention for the cubic (2 0 0) peak.
• Figure 5 shows X-ray theta-2theta diffractogram for a HIPIMS-deposited (Ti,AI)N layer for the cubic (2 0 0) peak.
• Figure 6 shows X-ray theta-2theta diffractogram for an arc-deposited
• Figure 7 shows X-ray theta-2theta diffractograms for a (Ti,AI)N layer as deposited and after different heat treatment temperatures.
• Figure 8 shows X-ray theta-2theta diffractograms for a (Ti,AI,Cr,Si)N layer according to the invention as deposited and after different heat treatment temperatures.
• a coated cutting tool comprising a substrate with a coating comprising a layer of (Ti,AI,Cr,Si)N, said (Ti,AI,Cr,Si)N comprising a cubic phase having more than one unit cell length.
• An averaged radial intensity profile is obtained from an electron diffraction pattern by providing an average of all intensities in the diffraction pattern with the same distance (radius) to the center of the diffraction pattern. Then, the averaged intensities are drawn as a function of the radius.
• the layer of (Ti,AI,Cr,Si)N of the present invention comprises a general cubic structure in which there are more than one lattice plane spacing present giving a (2 0 0) reflection.
• the presence of more than one unit cell length can be detected by XRD or TEM analysis (electron diffraction).
• XRD XRD
• TEM analysis electron diffraction
• the (2 0 0) reflection intensity is in one embodiment distributed so that three maximas are seen (see Figure 2).
• the maximas in this specific example of the invention correspond to d-spacings of 2.01 , 2.04 and 2.07 A. More than one maximum for other reflections, such as (1 1 1), (2 2 0) and (2 2 2), may also be present in embodiments of the present invention.
• the layer of Ti x Al y Cr z Si v N comprises a cubic phase which within the unit cell length range 3.96 to 4.22 A comprises from two to four intensity maxima in an intensity profile of an electron diffraction pattern.
• the layer of Ti x Al y Cr z Si v N comprises a cubic phase which within the unit cell length range 3.96 to 4.22 A comprises three intensity maxima in the intensity profile of an electron diffraction pattern, the maxima are situated within the ranges 4.00-4.04 A, 4.06-4.10 A and 4.12-4.16 A, respectively.
• x is preferably 0.35-0.45
• y is preferably 0.30-0.40
• z is preferably 0.08-0.13
• the layer of Ti x Al y Cr z Si v N has a hardness of from 3300 to 3700 HV, preferably from 3500 to 3700 HV.
• the layer of Ti x Al y Cr z Si v N has a reduced Young ' s modulus of 3 320 GPa, preferably 3 340 GPa.
• the layer of Ti x Al y Cr z Si v N has a residual stress of from -3 to
• the layer of Ti x Al y Cr z Si v N has a thermal conductivity of less than 3 W/mK, preferably from 1.8 to 2.8 W/mK.
• a low thermal conductivity is beneficial to keep the thermal load from the cutting process on the tool substrate as low as possible.
• the thickness of the layer of Ti x Al y Cr z Si v N is suitably from 0.5 to 6 pm, preferably from 1.5 to 4 pm.
• the thickness of the at least one metal nitride layer between the substrate and the layer of Ti x Al y Cr z Si v N is suitably from 0.1 to 3 pm, preferably from 0.5 to 2 pm.
• the substrate of the coated cutting tool can be of any kind common in the field of cutting tools for metal machining.
• the substrate is suitably selected from cemented carbide, cermet, cBN, ceramics, PCD and HSS.
• the substrate is cemented carbide.
• the coated cutting tool can be a coated cutting insert, such as a coated cutting insert for turning or a coated cutting insert for milling, or a coated cutting insert for drilling, or a coated cutting insert for threading, or a coated cutting insert for parting and grooving.
• the coated cutting tool can also be a coated solid tool such as a solid drill, an endmill, or a tap.
• the layer of Ti x Al y Cr z Si v N is preferably a sputter-deposited layer, most preferably a HIPIMS (High Power Impulse Magnetron Sputtering)-deposited layer.
• HIPIMS High Power Impulse Magnetron Sputtering
• a target containing all of the elements Ti, Al, Cr and Si is preferably used.
• the method of producing the coated cutting tool as herein disclosed comprises providing a substrate and depositing, preferably in HIPIMS mode, a layer of
• the peak power density is suitably > 0.2 kW/cm 2 , preferably > 0.4 kW/cm 2 , most preferably > 0.7 kW/cm 2
• the peak current density suitably > 0.2 A/cm 2 , preferably > 0.3 A/cm 2 , most preferably > 0.4 A/cm 2
• the maximum peak voltage suitably 300-1500 V, preferably 400-900 V.
• the substrate temperature during the deposition is suitably from 350 to 600°C, preferably from 400 to 550°C.
• the DC bias voltage used in a HIPIMS process is suitably 20-100 V, or 30-80 V (negative bias).
• the average power density in a HIPIMS process is suitably 20-110 W orn 2 , preferably 30-90 W orn 2 .
• the deposition process there is preferably used one or more targets of TiAICrSi, then of the same composition. In one embodiment three targets (one row) are used.
• a cross-section of the coating was analysed perpendicular to surface of the coating.
• the Time-Domain-Thermal Reflectance (TDTR)-Method was used which has the following characteristics:
• the thickness of a layer was determined by calotte grinding. Thereby a steel ball was used having a diameter of 30 mm for grinding the dome shaped recess and further the ring diameters were measured, and the layer thicknesses were calculated therefrom. Measurements of the layer thickness on the rake face (RF) of the cutting tool were carried out at a distance of 2000 pm from the corner, and measurements on the flank face (FF) were carried out in the middle of the flank face.
• RF rake face
• FF flank face
• a layer thickness of about 1 pm was deposited.
• Target size circular, diameter 15 cm (the effective area of the plasma was one third of the target area)
• the substrates had a composition of 8 wt% Co and balance WC.
• a layer thickness of about 3 pm was deposited.
• Example 2 The coated cutting tool provided is called “Sample 2 (reference)
• Example 3 Reference
• a (Ti,AI)N layer from a target with the composition Tio .33 Alo .67 was deposited onto WC-Co based substrates being cutting inserts of a milling type and as well flat inserts (for easier analysis of the coating).
• a layer thickness of about 3 pm was deposited.
• the coated cutting tool provided is called “Sample 3 (reference)"
• Ti,AI,Cr,SiN coating according to US 2015/023978 A1 was deposited by cathodic arc evaporation from a Tio.50Alo.50 target, a Alo.70Cro.30 target and a Tio.85Sio.15 target being a nano-multilayer of (approximately) Tio .50 Alo .50 N, Alo .70 Cro .30 N and
• the coating is made of an alternating multilayer A-B wherein layer A in itself is a nano-multilayer of sub-layers Alo .70 Cro .30 N and Tio .85 Sio .15 N each being about 7 nm.
• the thickness of A being about 56 nm.
• Layer B is a Tio.50Alo.50N layer with a thickness of about 50 nm.
• the layer sequence A-B is repeated 20 times.
• the total thickness of the coating is about 2 pm.
• the average composition of the (Ti,AI,Cr,Si)N coating being approximately Ti 0.45 AI 0.40 Cr 0.10 Si 0.05 N.
• the coating was deposited onto WC-Co based substrates being cutting inserts of a milling type and as well flat inserts (for easier analysis of the coating).
• the substrates had a composition of 8 wt% Co and balance WC.
• the deposition was made in an Innova PVD equipment from the manufacturer Oerlikon-Balzers.
• Layer B 2x Tio .50 Alo .50 N (two targets in the deposition chamber), process conditions:
• the coated cutting tool provided is called “Sample 4 (reference)”.
• Electron diffraction (TEM) analysis was made on Sample 1 (invention).
• Figure 1 shows the electron diffraction pattern obtained.
• Figure 2 shows a radial intensity distribution profile along a line A-B in the electron diffractogram of Sample 1 (invention).
• Figure 3 shows an averaged radial intensity distribution profile for the electron diffractogram of Sample 1 (invention).
• Figure 3a shows an enlarged image of the marked part, corresponding to the cubic (2 0 0) reflection, of figure 3.
• Figure 4 shows the X-ray theta-2theta diffractograms for Sample 1 (invention) in the 2theta range 40-45 degrees showing the cubic (2 0 0) peak.
• Figure 5 shows X-ray theta-2theta diffractogram for Sample 2 (reference), an HIPIMS-deposited (Ti,AI)N layer, in the 2theta range 40-45 degrees showing the cubic (2 0 0) peak.
• Figure 6 shows X-ray theta-2theta diffractogram for Sample 4 (reference), an arc-deposited (Ti,AI,Cr,Si)N layer, in the 2theta range 40-45 degrees showing the cubic (2 0 0) peak.
• Residual stress was also measured on Sample 1 (invention) showing a value of -5.1 +-0.3 GPa, i.e. , compressive.
• Hardness measurements (load 15 mN) were carried out on the flank face of the coated tool to determine Vickers hardness and reduced Young modulus (EIT). Table 2 shows the results. For characterization of toughness (Young's modulus) of the coatings Vickers indents with a load of 500 mN were carried out and cross section prepared. Table 2.
• the high temperature stability ef the HIPIMS-depesited (Ti,AI,Cr,Si)N layer accerding te the inventien, present in the ceating ef Sample 1 (inventien) was cempared with Sample 3 (reference), i.e., a HIPIMS-depesited (alsc S3p technclcgy) (Ti,AI)N ccating.
• the (Ti,AI,Cr,Si)N ccating was depcsited acccrding tc the prccess in Example 1. In this ccating, hewever, nc inner (Ti,AI)N layer was depcsited.
• the coated inserts were placed in a furnace tube and subjected to an annealilng procedure. The temperature was increased during one hour to a maximum temperature and then kept at that temperature for one hour. Within the furnance tube there was an argon pressure of about 2 bar. After heat treatment, there was no active cooling. The equipment for the experiment was from the manufacturer Nabertherm.
• the stability at high temperatures for the (Ti,AI,Cr,Si)N coating is also seen in XRD analysis.
• XRD measurements (theta-2theta analysis) were made on both the (Ti,AI)N coating and the (Ti,AI,Cr,Si)N coating in an as-deposited state, after annealing at 900°C, 1000°C, and 1100°C.
• Figure 7 shows the diffractograms for the (Ti,AI)N coating
• Figure 8 shows the diffractograms for the (Ti,AI,Cr,Si)N.
• Sample 4 (reference) was tested in a separate test round with the same cutting test parameters as testing Sample 1 and Sample 3 above, including the same workpiece material. The test had to be stopped already after a cutting length of 76 m due to a heavy wear seen as a VBmax of 0.25 mm.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Composite Materials (AREA)
• Manufacturing & Machinery (AREA)
• Cutting Tools, Boring Holders, And Turrets (AREA)
• Physical Vapour Deposition (AREA)

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• 2019
  • 2019-06-28 EP EP19183361.5A patent/EP3757252B1/en active Active
• 2020
  • 2020-06-24 KR KR1020217037523A patent/KR20220027055A/ko unknown
  • 2020-06-24 CN CN202080046655.6A patent/CN114026269B/zh active Active
  • 2020-06-24 US US17/622,376 patent/US20220259715A1/en active Pending
  • 2020-06-24 WO PCT/EP2020/067631 patent/WO2020260357A1/en active Application Filing

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